A little test to see what context an event listener is bound to when run.

test-emit-context.js

const events = require('events'),
    util = require('util');

function Test() {
    this.created = Date.now();
}
util.inherits(Test, events.EventEmitter);
Test.prototype.sendEmit = function() {
    this.emit("BOOM", Date.now(), this);
}

var t = new Test();
t.on('BOOM', function(time, t2) {
    console.log("I am in the context of t: ", (this == t));
});

setTimeout(function() { 
    t.sendEmit();
}, 100);

Results: the call back is run in the context of Test() yay.